1. Field of Invention
This invention relates to a writing display board. More specifically, the present invention is related to a writing board having a display area defined by a matrix of reversible magnets held in a parallel position to each other with the same magnetic orientation. The magnets are driven and repelled by more powerful magnets to either write or erase by moving a contrasting surface into or out of the observer's view.
2. Description of the Related Art
Display boards having magnetically reversible elements are known in the art. Such display boards are typically used as display signs and advertisements. The display boards of the prior art provide a large matrix of magnetically reversible elements which are not practically usefull as replacements for a conventional chalkboard, dry erase board, or other similar type of display board. In addition, such display boards are relatively complex and expensive.
Typical of the art are those devices disclosed in the following U.S. Patent Nos.:
U.S. Pat. No. Inventor(s) Issue Date 3,518,664 M. K. Taylor June 30, 1970 3,540,038 M. K. Taylor et al. Nov. l0, 1970 4,417,241 M. Wakatake Nov. 22, 1983 4,566,003 M. Wakatake Jan. 21, 1986 Re. 33,936 N. Miyamori et al. May 26, 1992 5,475,939 H. P. A. Salam Dec. 19, 1995 5,627,562 R. Skodlar May 6, 1997 5,642,130. J. Browne June 24, 1997 5,654,529 C. W. Yeung et a1. Aug. 5, 1997 5,717,515 N. K Sheridon Feb. 10, 1998 5,737,115 J. D. Mackinlay et al. Apr. 7, 1998 5,818,414 L. Jaki et al. Oct. 6, 1998 5,894,367 N. K. Sheridon Apr. 13, 1999 5,898,418 P. C. Kao Apr. 27, 1999 5,901,483 V. S. Tijanic May 11,1999
Of these patents, the '664 patent issued to Taylor discloses a magnetically actuable visual display surface having a magnetically biased matrix of elements. Each element is rotatable about an axis upon the application of a magnetic field. The magnetic field is reversible in order to return the element back to its original state. A subset of the elements is provided to define a region in which may be displayed a single pre-defined character comprised of a plurality of the elements.
The '038 patent issued to Taylor et al. discloses a similar device in which each magnetically actuable element includes a plurality of display surfaces, each displaying a unique color. Two rotatable elements cooperate to define four display surfaces. The two elements are independently and magnetically controlled in order to selectively display any one of the four colors. As in the previous device, each element is controlled in a predetermined pattern.
Wakatake ('241) discloses a magnetically operated matrix display panel that is comprised of a matrix of electromagnetically rotatable elements. Each element defines four display surfaces. Two erasing heads are slidably disposed behind the matrix of rotatable elements, the erasing heads being vertically slidable behind the display elements for re-orienting the elements to their initial orientation to "erase" the displayed image or message.
Wakatake ('003) also discloses a rotatable display board comprised of a cylindrical matrix of elements, a column of writing magnetic heads and a column of erasing magnetic heads. As the display board is rotated, the column of writing magnetic heads is electrically operated to selectively orient a corresponding column of display elements to a selected orientation. As the display board completes a rotation, the column of erasing magnetic heads returns each display element to its original orientation.
Reissue patent 33,936 issued to Miyamori et al. discloses an electronic blackboard apparatus. A conventional writing surface is provided with a writing instrument having a magnetic core, an eraser having a magnetic core, and a position-detecting control unit. As a user writes on the display surface, the position-detecting control unit detects the position of the writing implement relative to the blackboard. Position data is then stored, electronically displayed on a remote display screen, and/or printed onto a printable medium. While Miyamori et al. disclose a means for electronically storing data representing an image written on a blackboard, they do not disclose a display which is magnetically operable. Inherent problems associated with the use of a blackboard are likewise associated with the '936 device. Specifically, the '936 device requires consumable writing implements and cleaning the writing medium such as chalk and ink.
Skodlar ('562) discloses a magnetic display used as a label in applications such as a price tag for goods, a due date and/or time for movie rentals and library books, and the like. The label includes a display area with magnetic particles which can be oriented by an external magnetic field in the shape of a readable image. A portable writing apparatus includes an electrically controllable writing magnet and an electrically controllable erase magnet. The writing apparatus is placed proximate the display area of the label and the selected text is entered on a keyboard carried by the writing apparatus. The entered data are then processed and the write and/or erase magnets are electrically actuated to orient the magnetic particles within the display area of the label. Skodlar does not, however, disclose a device for randomly actuating the individual magnetic particles to form handwritten or drawn image.
Browne ('130) discloses a display array and power control circuit similar to that of the Taylor devices described above. Browne further discloses the use of a Hall effect switch to control each of the magnetically actuated elements. A light source is also disclosed to augment the appearance of an individual element when oriented in a selected viewing orientation.
Salam ('939) also discloses a matrix display device which incorporates an illumination source. In the '939 device, the illumination source is an array of back-lit diffusers to correspond with the array of rotatable reflective vanes which are carried on a removable display sheet.
Yeung et al. ('529) disclose a handheld computing device having a planar display and a superimposed, transparent digitizer. A passive stylus is used to press on and move across the surface of the display in order to simulate writing or drawing. As the stylus is so moved, a line is produced directly under the path of the stylus. An inductive winding under the display surface is provided for inducing a small voltage under the path of a magnet disposed on one end of the stylus in order to erase a selected portion of the display. The images drawn on the display are digitized and stored as collected data for further use such as remote display, future retrieval and display, or for printing.
The '515 and '367 devices disclosed by Sheridon and the '115 device disclosed by Mackinlay et al. are electrode assemblies for an addressable light-modulating apparatus, wherein the light-modulating apparatus is a gyricon made up of electrically and optically anisotropic spheroidal balls rotatably disposed in a substrate. Each spheroidal ball is bounded by four edges, each edge being electrically connected to an electrode assembly such that a discrete electrical potential is applicable to each edge in order to orient the ball in four selected orientations. The orientation of each of the balls is controlled electrically.
Jaki et al. ('414) disclose a single display device having passive components for displaying characters consisting of a plurality of matrix-arranged picture elements. Each display element is constructed of a generally cylindrical body mounted to swivel about its centroidal axis. An operating coil is provided behind each display element for applying a magnetic field to the element for rotating the same.
The device disclosed by Kao ('418) is a magnetically operated display element. The element includes a frame of one color and a pivotally mounted plate having a first side of the same color as the frame and a second side of a second color. A ferromagnetic element is carried by the frame to cooperate with a,magnetic member carried by the plate to accomplish pivoting of the plate. An LED is associated with the device and is illuminated when the plate is pivoted to reveal the second side thereof, thereby illuminating only those elements that comprise the selected text and or images. The device disclosed by Tijanic ('483) is similar to the '418 device. Both of these devices are electrically operated for displaying pre-determined text messages or images.
Other devices similar to those discussed above are known in the art. While these devices teach the use of magnetically-actuated image display elements, none discloses a writing unit having magnetically-actuated image elements which allow for selective writing and erasure, as well as marking either directly by a person holding a writing and erasure apparatus, inputting into a computer and transferring to the writing surface, using a combination of both input options, or transferring images from the writing board to a computer. Further, the prior art fails to teach a writing board having magnetically-actuated display elements wherein text and images displayed on the board surface remain until the writer desires to erase. Each of the prior art devices requires electric power to operate each display element, and fails to teach a means for generating a display comprised of magnetically-actuated elements without the requirement of electrical power.
Therefore, it is an object of the present invention to provide a writing board including a matrix of magnetically-actuated display elements each controlled by a magnetic writing implement.
Another object of the present invention is to provide such a writing board wherein each magnetically-actuated display element defines a size such that the density of the matrix is sufficient to enable the writing board to be used as a suitable replacement of a chalk board or dry erase board.
It is also an object of the present invention to provide such a writing board wherein each display element is electrically controllable to display a pre-selected display, and to store data corresponding to a display generated on the display screen using the magnetic writing implement.
A further object of the present invention is to provide a writing board having magnetically-actuated display elements whereby selected portions or all of the magnetically-actuated display elements are immediately actuable to "erase" portions or all of a display.
As such, it is an object of the present invention to provide such a writing board wherein electrical power is required only for the display of a pre-selected display and for downloading and storing data corresponding to an image, and wherein no electrical power is required for the generation of a display image using the magnetic writing implement.
Due to the use of magnetic display elements, it is also an object of the present invention to provide a writing board devoid of residue resulting from conventional writing boards such as chalk and marker boards.
It is also an object of the present invention to provide a writing board which is comprised of simple mechanical movements having relatively few parts susceptible to failure.
Other objects and advantages over the prior art will become apparent to those skilled in the art upon reading the detailed description together with the drawings as described as follows.